.TH io_readwritefile 3
.SH NAME
io_readfile \- open a file for reading and writing
.SH SYNTAX
.B #include <libowfat/io.h>

int \fBio_readwritefile\fP(int64* d,const char* filename);
.SH DESCRIPTION
io_readwritefile sets d to the number of a new descriptor reading from
and writing to the disk file named \fIfilename\fR, and returns 1.  The file
needs to exist.

If something goes wrong, io_readwritefile sets \fIerrno\fR to indicate the error, and
returns 0; it does not create a new descriptor, and it does not touch d.
.SH "SEE ALSO"
io_readfile(3), io_createfile(3), io_appendfile(3)
